Pivotally mounted sling stirrup bail



March 18, 1969 H, scH E 3,433,522

PIVOTALLY MOUNTED SLING STIRRUP BAIL Filed Feb. 20, 1967 INVENTOR. HERBERT A. RASCHKE lownsznci ml iownsend v .A TTORNE Y8 United States Patent 1 Claim Int. Cl. B66c 1/36 ABSTRACT OF THE DISCLOSURE A generally U-shaped bail for affording attachment of a fabric sling to a load. A removable pin spanning the legs of the bail for affording removable attachment of a sling to the bail. A U-shaped bail adapted for pivotal attachment to a hook or like load engaging member.

This invention relates to a bail for effecting attachment of a web sling or like flat, flexible tension member to a load engaging member.

With the development of synthetic fibers of extremely high strength, such as nylon, slings and loops formed from such material have found wide application in hoisting loads. For example, the width of such material distributes the weight over a broad area as contrasted with steel cables formally used for this purpose so that damage to the load is reduced or eliminated by the wide slings. Additionally such slings are more flexible than steel cables slings of corresponding strength and therefore grip a load more uniformly and securely. Full utilization of fabric slings has not been realized, however, because eyes or loops provided on existing hoisting equipment do not distribute the tension force uniformly over the width of the fabric sling. As a consequence, slings of the type mentioned have either been substantially de-rated or require special modifications at the portions thereof that engage loops or stirrups in hoisting apparatus.

Therefore, it is an object of this invention to provide a bail or stirrup that is especially adapted for attaching flexible slings to rigid members in hoisting structures. This object is achieved by providing a generally U-shaped stirrup member that has two legs in parallel spaced relation which define at the free ends thereof coaxial bores for receipt of a cross pin therein. The parallel legs are spaced apart by an amount approximately equal to the width of a web sling so that the sling engages the cross pin uniformly across the width of the sling. The cross pin is removably secured in the bail so that a continuous fabric sling or looped fabric sling can be attached to the device without cutting, sewing or otherwise fastening the fabric material of which the sling is made.

Another object is to provide a bail for securing webbing to objects which bail is adapted to be pivotally mounted to existing devices such as hooks and the like. This object is achieved by providing a U-shaped bail that is bored centrally of the base of the U so that the force of tension is imposed symmetrically of the bail and webbing, and symmetrically of the device to which the bail is pivotally attached.

Still another object of the invention is to provide a bail or stirrup of exceedingly high strength. Contributing to this object is a U-shaped structure having a generally curved base, a shape substantially free of stress concentrations. Centrally of the U-shaped curved portion is formed a counterbore that defines a flat circular surface which forms a bearing surface so as to expedite mounting of the bail to a load carrying member so that the bail is pivotable with respect to such member.

Yet another object is to provide a U-shaped bail of such configuration that the bail will not foul on guys or like protrusions when a load is hoisted through a congested environment. The above mentioned U-shaped configuration of the bail contributes to achievement of this object as do recessed fasteners for the cross pin that spans the free ends of the legs of the U-shaped member. Accordingly, the cross pin is contained solely within the confines of the U-shaped member, thereby avoiding protrusions of the type that are likely to catch or foul on obstructions in the environment through which a load is being hoisted by'the apparatus of the invention.

These and other objects will be more apparent after referring to the following specification and accompanying drawing in which:'

FIG. 1 is a side elevation view of a bail according to the present invention shown mounted on a hoisting hook;

FIG. 2 is a fragmentary side view of FIG. 1;

FIG. 3 is a cross sectional view taken on line 3-3 of FIG. 2;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 2; and

FIG. 5 is a diagrammatic view showing the stirrup of the present invention in another hoisting application.

Referring more particularly to the drawing, reference numeral 12 indicates generally a bail according to the present invention which is shown in FIG. 1 as being mounted to a conventional hoisting hook 14 that has a cylindric shank 16 extending therefrom and integral therewith. A gate 18 is rotatively supported on shank 16 and is adapted to selectively close the throat opening of hook 14. A spacer 19 is disposed between the gate and the bail to afford relative pivotal movement of the parts.

Bail 12 is of generally U-shaped configuration and has a base 20 from which extends a pair of legs 22 and 24. As can be seen most clearly in FIG. 1, legs 22 and 24 are mutually parallel and are generally perpendicular to base leg 20. At their respective free ends 26 and 28, legs 22 and 24 are crossbored, as at 30, to receive a pin 32 therein. A sleeve 34, having an inside diameter substantially equal to the outside diameter of pin 32, is mounted on the pin so as to provide rolling movement between a web loop L and bail 12. The rotative movement afforded by the smooth inner surface of sleeve 34 and the smooth outer surface of pin 32 enhances the uniformity of loading across the webbing.

At the outer surface of free ends 26 and 28, a counterbore 36 is formed, and a retaining ring 38 is provided in engagement with an annular slot 40 in the end of pin 32. Ring 38 retains pin 32 within bail 12 and against longitudial movement. It will be noted that the end of pin 32 terminates inwardlyof the outer surface of leg 22 so as to avoid any protrusion from such surface.

In order to provide further assurance that the tension on web loop L is imposed on the webbing uniformly across the width thereof, base piece 20 of U-shaped bail 12 is bored at 42, centrally of the base leg and midway between legs 22 and 24. The upper or inner face of bail 12 is oounterbored at 44 to define a smooth bearing surface on which bears a flat bushing or washer 46. Counterbore 44 is essential because the inner face of U-shaped bail 12 is smoothly curved, as can be seen at 48, so as to avoid stress concentrations in the bail. The pivotal joint between hook shank 16 and bail 12 is completed by a nut 50 that is threaded onto the end of the shank remote from hook 14. Thus, a freely pivotal connection is afforded between bail 12 and the hook, which connection is symmetrical with respect to legs 22 and 24 so that the tension on sling loop L is uniformly distributed thereacross. Moreover, stress concentration within the bail is substantially avoided because of the continuously curved configuration 48 of base leg 20 of the bail.

Another application for the present invention is shown in FIG. 5 wherein a spreader bar 52 of conventional form is shownprovided with a plurality of bails 12 mounted thereto. Each bail 12 is mounted tospreader bar 52 by means of a bolt 56 that has a nut identical to nut 50 shown in FIG. 4 as well as a bushing or washer 46. Accordingly, the bails 12 are secured to bar 52 for pivotal movement relative to the bar. Connected to associated pairs of bails 12 are looped straps 58 and 60 so as to adapt the particular configuration of FIG. 5 for lifting long objects, such as a bundle of steel reinforcing bars or the like.

The bar 52 has extending upwardly therefrom at opposite ends thereof a pair of bails 12 for joining web sling 62 to the bar, the sling at its mid point being engaged by a hoisting line 64. By the use of bails 12 in the assembly of FIG. 5, it will be seen that, as is the case of the invention as described in connection with FIG. 1, each of the webs is uniformly loaded across its width and each web can be conveniently installed or removed by simple removal of cross pin 32 in each of the bails.

Thus, it will be seen that the present invention provides an improved bail that is adapted to accommodate fabric slings to lifting structures that have heretofore been substantially limited to cables or fabric slings that have specially woven eyes or loops. Such advantageous feature is secured by an extremely straight forward and rugged structure which can be accommodated to existing equip ment, such as hooks and spreader bars and the like, without substantial modification of such existing equipment.

Although one embodiment of my invention has been shown and described, it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

1 claim:

1. A hoisting hook mountable on a loop of flat, flexible webbing material comprising a load engaging hook having a cylindric shank integral therewith and extending therefrom, a bail including a base member having a hole centrally thereof for receipt of said shank and a counterbore defining a bearing surface concentric with said hole, means engageable with said shank for retaining said bail thereto and for affording relative rotative movement therebetween, said retaining means including a fiat bushing engageable with said bearing surface for effecting transfer of the load on said hook to said bail uniformly over a large area, said bail having first and second legs integral therewith and parallelly extending therefrom in symmetry to said bearing surface, said legs being bored at the ends thereof remote from said base member along a common axis normal to said shank, a pin receivable in said bores in spanning relation to the space between said legs for circumscribing engagement by a loop of fiat, flexible webbing, means for removably retaining said pin in said bore, said legs having counterbores concentric with the bores therein and on the outer surface thereof, and said retaining means being totally recessed in said counterbores, and a sleeve on said pin between said legs to afford rotative movement between said bail and webbing material.

References Cited UNITED STATES PATENTS 175,572 4/1876 Machin 29482 X 739,901 9/ 1903 Myers 29474 2,196,460 4/ 1940 Hertel 29482 2,375,719 5/1945 Wirkkala 294 78 3,083,991 4/ 1963 Gale 29474 X 3,120,403 2/ 1964 Molzan et al 29474 3,343,862 9/1967 Holmes 29474 ANDRES H. NIELSEN, Primary Examiner. 

